Figuring out YOUR personal calorie burn. Accurately.

Friday, December 23, 2011

I read a lot of blog posts and forum messages from people who feel confused and dismayed about plateaus and slow weight loss. Knowing your personal total calorie burn is important so you can figure out how much to eat - so you can set up an appropriate calorie deficit for losing, or set a target to maintain.

There are tools available here at SP for estimating your basal metabolic rate and calorie burn through exercise, etc. Unfortunately they can be wildly inaccurate because they are based on formulas for average humans and not based on YOU, individually.

You take the calories eaten and compare it to what your weight is doing on the scale.

Suppose you are eating on average 1600 calories per day and losing about 1.6 pounds per week.

1.6 pounds is roughly equivalent to 3500 calories times 1.6 = 5600 calories. So if you're losing about 5600 calories per week, divide that by seven to figure out your daily average deficit. In this case that is about 800 calories.

So if you're taking in about 1600 calories per day and are 800 calories below your daily needs, that means your daily calorie needs are about 1600+800 = 2400 calories.

Suppose you're eating about 2000 calories per day and gaining about 0.5 pounds per week?

0.5 pounds times 3500 calories is about 1750 extra calories per week. Divide that by seven and it is about 250 calories extra per day.

Those numbers would mean that your total burn is about 2000 - 250 = 1750 calories per day.

Suppose you are eating about 2100 calories per day and have been at a plateau for about 2 weeks. That makes the math really easy. It means you're burning roughly what you're eating, 2100 calories.

There are a few requirements to make this work. And you need to apply them consistently over weeks in order to figure out what is going on with your body.

1) You need to have a fairly consistent exercise routine. If you collect the numbers while training for a triathlon and then try to apply them during a 2 week cruise in the tropics, your estimates will be off.

2) You need to track your food. ALL of your food. And you need to track it accurately. If you don't know how much you are eating, you can't figure out how much you are burning. Because I love accuracy so much, I weigh everything I eat; using cups and teaspoons isn't as precise.

3) You need an accurate estimate of your weight. Daily fluctuations due to hydration can be as much as 2%. Weighing yourself once a week will help you see a downward or upward trend, but it won't take out the +/- 2% error problem for each measurement.

Because of this I like to use a weighted moving average of my daily weight. There are a number of free sites that can calculate this for you.

However you do the tracking of your weight and food, you need to do it accurately and consistently. The better your data, the more clearly you will be able to understand the results.

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So, after a week or so, figure out your average calories eaten and how much you're burning or storing based on your weight. With those numbers you can calculate an appropriate deficit. Most sources recommend a deficit of about 500 calories per day to lose about a pound a week.

Now that I'm back in maintenance range it's even more important to have accurate estimates for my calorie needs - I have to know how much to eat!

That first example above is actually me. I've been eating about 1600 calories per day and losing about 1.6 lbs per week. My plan is to raise my eating target by 100 calories each week. So next Monday I'll target 1700 calories per day and see what happens. The week after that I'll target 1800 calories per day.

Since I started about 800 calories below my needs it should take about two months to stabilize, assuming my activity levels remain about the same. I estimate that I'll lose about 7 more pounds during those two months, and it should taper off to almost no weight change from week to week.

If I get sidelined by injury or illness my burn rate will drop. If I end up being more active than this my burn rate will go up. So I'll be watching the numbers carefully.

*I wear 5 lbs on each ankle & wrist for Tae Kardio. I take the seat off the spin bike and do the whole class standing and hovering. I lift as heavy as I can in Body Pump without losing form.
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Having said all this, I need to add a disclaimer that this whole endeavor is not really about the number on the scale at all. The number on the scale is just a convenient, rough indicator. What I really care about is body composition and athletic performance.

How you control that is with WHAT you eat, and HOW you burn your calories. And tracking it is a much more difficult can of worms.

DRB13_1
thanks for the sparkmail & for sharing your expertise (YES, your weight loss success makes you an expert!)I love the final statement - body composition & athletic performance. I am not defined by a number. I am prouder of completing a half marathon than having a number on the scale I think I should reach.1562 days ago

FROGGGY13
This is great and appeals to the scientist in me. For a while now, I've known there was something off with my equations : either I am burning more than SP says, or underestimating calories. Maybe I should weigh foods. I am very nervous about regaining, but really want to know what's going on.1811 days ago

MOBYCARP
Great blog! I was aware of the general ideas, but I'm not rigorous enough to run down the systems that you link to.

I think I'd still have issues trying to track things in fine detail, primarily from my exercise not being totally consistent from week to week; but the concepts you describe are vitally important for understanding what's going on.1811 days ago

RG_DFW
Thanks, I've enjoyed the discourse over the last few days. Although I'm starting my tracking-in-earnest during the holidays, it becomes the start of the answer to the last thirty pounds and maintenance thereafter.

I've even started the fitness ladder... thanks for pointing me in this direction!!1812 days ago

CCKELLY3
Oh boy, a bunch of new toys to play with if I decide to go a few more pounds. I've always found ways to enjoy the tracking process, mostly by the charts and graphs to show the progress as well as being able to look back at trends, which over time give real insight into how your body works best. But it never occurred to me that part of this is that I like accuracy-- just like you, I've been weighing my food by the grams for the past few years, and charting that way, and have had great success with it. So much so that even though I've been in maintenance for almost a year now, I still like to do most of my at home food that way, whether I need to or not.

Anyway, glad to hear you're doing well and on track! And thanks for the new tools and ideas of how to think about this- seriously, like new toys! :0)

BREWMASTERBILL
"What does prompt me to adjust my calories is hunger. Real hunger strong enough to make it hard to fall asleep or something. If that happens I up my calories the next day because too much of that tends to lead to binges for me. "

I'm noticing this pattern in me this go around. I can keep them pretty well under control, but yesterday I ate at maintenance because the hunger was getting in the way of making a living. Today, I'm able to go back to a deficit without issue. I guess this is a point for the calorie cycling folks.1812 days ago

And unless I'm doing something super strenuous like cycling 100 miles in a day or something, the calorie burn estimates from the HR monitor don't track at all with the overall estimated burn rate. I still track it anyway because it helps with affecting body composition, but that's a different issue.

Usually when I dropped two or three pounds in a day it was related to hydration; because I'm using a BIA scale to estimate % body fat and that measurement is hydration-dependent, I can usually tell; a rapid drop in weight is usually accompanied by an apparent jump in % body fat (which isn't real, but just because I have less water in my system than usual).

So I don't adjust my calories on the basis of that because it usually levels out eventually.

What does prompt me to adjust my calories is hunger. Real hunger strong enough to make it hard to fall asleep or something. If that happens I up my calories the next day because too much of that tends to lead to binges for me.

BLUE42DOWN
I use the Hacker's Diet log for tracking my weight daily and love being able to view the Trend rather than obsess about the ups and downs. It does have some very good information.

One thing I've found by reading SparkPeople's own articles is that the more active we are, the more possibility the calorie burn numbers will be higher than accurate.

Why?

Because those numbers INCLUDE the basal metabolic rate. We don't stop burning calories through normal living functions while we're exercising. For someone who works out 20 minutes a day, the padding is minute. For someone who works out 2 hours a day, it really adds up. (This is also why they don't have categories for things like sleeping, washing dishes, and the like. Those are part of the usual expected BMR.)

I definitely adjust on the fly, usually within my calorie range, but based on calories over the week and how much adjustment I want. When I suddenly drop 3 pounds one day and another pound the next, I start eating higher in my range. As it levels out, I drop back down to the middle. Sounds crazy to some people, but I actively work to AVOID a Trend higher than 2 pounds a week - preferring to be 1 to 1.5 pounds a week.1812 days ago

BREWMASTERBILL
I like it. I went a similar path when I was trying to find my maintenance calories. I ran into 1 problem that might cause some confusion (I mentioned in the HIT group many moons ago) and that is the equilibrium line is not linear. In other words, I could (from what I could tell) consume within a range of calories, say 2200-2400 per day and keep the same weight. So wth, 2400 calories is more than 2200 so what gives? I thought it was calories in/calories out. Well, it still is. I came across people with similar problems and the current theory flying around is NEAT. More calories = potentially more semi or totally involuntary action. More foot bouncing, higher core temp for example.

So just wanted to point out that little potential variable.1813 days ago